This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. In this project, the hydrodynamic radius of several dextrans of various length are determined. The hydrodynamic radius is relevant to diffusion studies of labeled dextrans in neuronal systems, where the molecular radius is a determining factor in gap junction permeability.